Bearings are used in various applications in which one object rotates with respect to another. An inner race is received in an outer race such that a radially-outward facing bearing surface of the inner race bears on a radially-inward facing bearing surface of the outer race. Usually, the inner race and outer race are affixed to other objects which can rotate relative to one another and, in some instances, the bearing surfaces are shaped such that there may be some axial misalignment between the inner race and the outer race during operation.
In many instances, to allow this axial misalignment during operation of the bearing assembly, the inner race has a frusto-spherical bearing surface that is captured in a negatively-shaped frusto-spherical bearing surface of the outer race. Given this geometry of the bearing surfaces, to accommodate insertion of the inner race into the outer race during assembly, the outer race often includes a pair of opposing entry slots on one axial face such that the inner race can fit through the slots of the outer race when the inner race is rotated approximately ninety degrees relative to the central axis of the outer race (i.e., the insertion of the inner race into the outer race occurs in an orientation where the inner race is perpendicular to its preferred rotation axis, which would generally align with the axis of outer race). To provide the required clearance during insertion, the sides of the inner race are typically truncated to generally correspond to, but to be slightly smaller than, the slot width of the opposing entry slots. This truncation gives the inner race a frusto-spherical shape. Once the inner race is inserted into the outer race, the inner race is turned 90 degrees to align with the outer race and the inner race is then sealed into the outer race to prevent the ingress of debris into the bearing space. At this point, the slotted entry bearing is ready for operation.